1. Field of the Invention:
The presnt invention relates to a diaphragm-type fuel pump with a built-in fuel filter.
2. Description of the Prior Art:
Diaphragm-type fuel pumps are used in internal combustion engines for automobiles. There are strong demands for smaller-size and lighter diaphragm-type fuel pumps to meet improved fuel economy and energy-saving requirements on automobiles.
To meet the above demands, efforts have been made to reduce the weight of various parts of the fuel pump by using drawn metal-sheet products instead of die casting. It has also been proposed to use parts partly constructed of synthetic resin.
Fuel supply systems for internal combustion engines include a fuel filter for removing dust or other foreign matter from fuel to be fed to the carburetor. The recent trend in the industry is that the fuel filter is incorporated in the fuel pump to meet the demand for the lighter assembly.
However, conventional fuel filters assembled in fuel pumps have the following drawbacks:
It is most important for such fuel filters to allow the fuel pump to be assembled with ease. The prior fuel filter, however, has not been designed to meet such a requirement. The conventional fuel filter construction does not permit easy filter replacement which should be made at frequent intervals. Furthermore, the diameter of the overall fuel pump should be reduced to reduce the size and weight of the fuel pump. The fuel pump is required to be constructed so that the volumes of inlet and outlet chambers may freely be selected for allowing the pump to be designed more easily, and is also required to have good performance.